According to the O'Kelly's Crack maxum (first 10 feet don't count toward the rating), this route should be 5.9! The bottom is hard (and has gotten a bit harder as the ground at the base has eroded away over the years).

Bouldery move off the ground to a couple nasty/greasy tips locks moves or a few lieback moves. Feels about the same difficulty whether you lieback or lock, just decide whether you want insecure hands or insecure feet.